Recovery of bioactives from kānuka leaves using subcritical water extraction: Techno-economic analysis, environmental impact assessment and technology readiness level

The techno-economic feasibility (TEA), technology readiness level (TRL), and environmental impact of producing bioactive kānuka leaf extracts using subcritical water extraction (SWE) were assessed and compared to using conventional ethanol extraction (EE). Both SWE and EE had the same TRL value from the analysis. The TEA showed that though EE required more process units, the total capital expenditure for SWE was still 3% higher than for EE. However, the manufacturing and unit cost of production were NZ$4.49 million and NZ$ 2.14/kg for SWE and NZ$4.7 million and NZ$ 5.57/kg for EE, respectively. The net present value for SWE was twice the value for EE. Sensitivity analysis revealed that the raw materials cost and product sales price were the controlling factors for profitability. Kānuka extract production with SWE was more environmentally benign than EE. Overall, producing bioactive kānuka extracts with SWE had better profitability with a shorter payback time than EE.